Magnetic Detergent

Scientists have long been searching for a way to control surfactants once they are in solution to increase their ability to dissolve oils in water and then remove them from a system. Surfactants sensitive to light, carbon dioxide or changes in pH, temperature or pressure have all been investigated. Bristol University scientists have produced the world's first magnetic surfactant by dissolving iron in inert detergents composed of chloride and bromide ions. The addition of the iron creates magnetic centres within the detergent particles.

To test the properties of their magnetic detergent, the scientists introduced a magnet to a test tube containing their new detergent lying beneath a less dense organic solution. When the magnet was introduced the iron-rich detergent overcame both gravity and surface tension between the water and oil, to levitate through the organic solvent and reach the source of the magnetic energy, demonstrating its magnetic properties.

Commercial development of magnetic detergents could be a big bonus for the environment. In the future oil spills could be cleaned up using magnetic detergents, and the oildetergent mixture removed using magnets.

Reference
Paul Brown, Alexey Bushmelev, Craig P. Butts, Jing Cheng, Julian Eastoe, Isabelle Grillo, Richard K. Heenan, Annette M. Schmidt. Magnetic Control over Liquid Surface Properties with Responsive Surfactants. Angewandte Chemie International Edition, 2012; DOI: 10.1002/anie.201108010

Further Reading
Soaps and Saponification
Detergents
Transition Metals
Ligands and Complex Ions

Suggested Study Questions

1. What other elements, besides iron, could be used to produce magnetic detergents?
   
2. Use the concept of the micelle to explain how iron can create magnetic centres within these new detergent mixtures.
3. For the experiment described in the second paragraph,
   
   • write a suitable aim
   • write a suitable method (procedure)
   • draw the results of the experiment as described
   • write a suitable conclusion
4. You have been asked to determine the effectiveness of this new magnetic detergent at different pH levels.
   • Write a suitable hypothesis.
     
   • If you were to undertake an experiment to test this hypothesis, what variables would need to be controlled?
     

5. You have been asked to determine the effectiveness of this new magnetic detergent at different pH levels.

   • write a suitable aim
   • write a suitable method (procedure)

6. Surfactants sensitive to light, carbon dioxide or changes in pH, temperature or pressure have all been investigated. Why do you think that a magnetic surfactant might be a better alternative for cleaning up oil spills in natural waterways?

7. What disadvantages can you see in using magnetic surfactants in cleaning up oil spills?